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 Post subject: ST205 Brake Booster Flex
PostPosted: Sun Jul 29, 2012 4:28 pm 
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Location: Perth, Western Australia
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two_OH_five wrote:
the reason the 205 has a spongy brake pedal is flex in the brake booster

Any more details, measurements etc?

Some time ago a guy made up a number of ST205 brake booster braces so I got hold of one. At the time it wasn't clear how effective it would be. I never got around to fitting it. Perhaps its worth re-considering?

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 Post subject:
PostPosted: Sun Jul 29, 2012 5:32 pm 
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Location: drinking devil fuel
Car Model: ST205
Don't have anything technical so will take a loss of anoracsia points on the chin

I would guesstimate one or two mm of master cylinder movement which means a lot of pedal movement

If you tread on the pedal hard you can visibly see the servo bulge :shock:
At the same time you can feel the pedal change from increasing effort to constant effort but still moving

It is consistent on both my cars and the servos are visually in good mechanical condition externally

I've long complained about poor pedal feel but have never noticed servo flex before


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 Post subject:
PostPosted: Sun Jul 29, 2012 5:40 pm 
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Interesting! This has long been rumoured/suspected. Fortunately we have ditched the servo on my tracktoy project :D Just need to strengthen leg muscles now :P Would be nice to get a firmer pedal on the road car.

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1994 Toyota Celica GT-Four ST205WRC JDM 269bhp @ 0.9bar
1994 Toyota Celica GT-Four Special GT 590bhp @ 1.8bar
1989 Van Diemen RF88/89 Formula Ford 1600
2008 Nissan Patrol GU 3.0L ZD30DDTi 154bhp


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 Post subject:
PostPosted: Fri Aug 10, 2012 7:31 am 
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Group N
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Location: Chirnside, Scottish Borders
Car Model: ST205
You still got the brace? get it fitted and see what its like man!!! :)

On the track next sunday for my 1st outing on the 205, looking forward to seeing how the brakes perform compared to the 185.I'm guessing its way better but I see brake fade as a challenge rather than bad! if it ain't there I'm not going fast enough :D

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 Post subject:
PostPosted: Fri Aug 10, 2012 7:54 pm 
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I'll try and locate it in my huge pile of parts! I've never found the brakes to be lacking, even on my standard setup and cement pads on the high speed Donington GP circuit :D It's just the slightly vague marshmallow feel that takes a bit of acclimatising. Have fun!

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1994 Toyota Celica GT-Four ST205WRC JDM 269bhp @ 0.9bar
1994 Toyota Celica GT-Four Special GT 590bhp @ 1.8bar
1989 Van Diemen RF88/89 Formula Ford 1600
2008 Nissan Patrol GU 3.0L ZD30DDTi 154bhp


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 Post subject:
PostPosted: Fri Aug 10, 2012 8:38 pm 
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I don't think the ST185 suffers as bad as the ST205 WRT marshmallow brake pedal - I had always assumed this was due to the ABS as my Non -ABS RC has a really hard brake pedal.

I wonder what the differences are?

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 Post subject:
PostPosted: Fri Aug 10, 2012 9:56 pm 
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Possibly because when you press on the pedal in a 205 the car slows down so you press harder
On a 185 pressing the pedal just creates clouds of smoke and a distressing smell so you press less hard and take the more amenable chicane avoidance lane :lol:


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 Post subject:
PostPosted: Fri Aug 10, 2012 10:13 pm 
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Hmm, fair point. My 185 is akin to pressing two blocks of wood against the disc both in feel and effect!

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 Post subject:
PostPosted: Fri Aug 10, 2012 10:18 pm 
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Location: Basingstoke
Car Model: ST185
Diceman wrote:
Hmm, fair point. My 185 is akin to pressing two blocks of wood against the disc both in feel and effect!


I'm actually surprised that you can remember :wink:

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 Post subject:
PostPosted: Fri Aug 10, 2012 10:29 pm 
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You'll keep :-)

I seem to remember an interesting test drive with you Clive - me driving and roundabout approaching quickly as I hadn't factored in the lack of brakes on the 185!

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 Post subject:
PostPosted: Sun Aug 12, 2012 11:32 pm 
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Location: drinking devil fuel
Car Model: ST205
Before pressing pedal
Image
Image

After
Image
Image

Definitely some movement there.
I reckon 2mm was pretty much bob on. I haven't worked out the pedal ratio so can't translate this into pedal movement


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 Post subject:
PostPosted: Wed Aug 22, 2012 11:18 am 
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There is a guy selling a TOM's ST205 brake master stopper brace thing on ebay at the mo if its of any use :)


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 Post subject:
PostPosted: Wed Aug 22, 2012 1:48 pm 
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Location: Camberley, Surrey
Car Model: ST205
Do you have a link? I can't find it!

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 Post subject:
PostPosted: Wed Aug 22, 2012 3:00 pm 
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Item number: 390456607858

:)


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 Post subject:
PostPosted: Wed Aug 22, 2012 3:20 pm 
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I'm forked if I can picture how or where that bolts on


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